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node 爬虫 实战 - 爬取拉勾网职位数据，主要想把数据用于大数据学习，到时候大数据分析可以自己分析一下职位的情况，和比较一些我现在的职位在深圳乃至全国的开发人员水平。
涉及到的技术栈：node.js ，mongoDB , express
源码下载：https://gitee.com/draven_lee/node-spider ，如果有帮助到你，不需要打赏，欢迎给star。
这个爬虫功能有点简单，仅供学习参考。
- 爬取lagou.com首页的menu菜单的url，并且把menu的前30页url保存进去爬虫队列中，之后沿着队列的url，把需要的数据提取出来。
- 爬取的过程中，发现，如果太频繁的和没有用户的登录态，会被和谐到其他页面去，应该是拉勾网做了防爬虫机制，所以我把爬取的速度放慢，加上模拟的登录态，可以成功爬取到数据。不过按照这个爬取有点慢的速度，我爬了四天四夜，爬了10W+条职位数据。
废话不说，先上代码。
var express = require('express');
var MongoClient = require('mongodb').MongoClient;
const request = require('superagent');
var url = "mongodb://localhost:27017/draven";
var router = express.Router();
var cheerio = require('cheerio');
var Crawler = require("crawler");
//爬取 数据
router.get('/crawlData', function(req, res, next) {
var url = "mongodb://localhost:27017/draven";
var menuList = [];
var urlList = []
var location = '深圳';
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("draven");
var c = new Crawler({
preRequest: function(options, done) {
// 'options' here is not the 'options' you pass to 'c.queue', instead, it's the options that is going to be passed to 'request' module
console.log(options.uri);
// when done is called, the request will start
done();
},
jQuery: true, //是否用 cheerio 的jQuery语法
rateLimit:25000, //爬取速度 25秒 爬一次
maxConnections : 1, //最大爬取并发量 1
headers:{ //模拟真实用户浏览器状态
'Cookie':'index_location_city='+encodeURI(location)+'user_trace_token=20181127172617-5d56fc60-618b-4486-9762-21efad3c49df; JSESSIONID=ABAAABAAAFCAAEG70DFEA8B139FF80287ABDF2F4C137946; showExpriedIndex=1; showExpriedCompanyHome=1; showExpriedMyPublish=1; index_location_city=%E6%B7%B1%E5%9C%B3; _ga=GA1.2.405959562.1543310779; _gid=GA1.2.577762828.1543310779; Hm_lvt_4233e74dff0ae5bd0a3d81c6ccf756e6=1543310402,1543310779; LGSID=20181127172618-7ef404ed-f226-11e8-80e4-525400f775ce; PRE_UTM=; PRE_HOST=; PRE_SITE=; PRE_LAND=https%3A%2F%2Fwww.lagou.com%2F; LGUID=20181127172618-7ef406c2-f226-11e8-80e4-525400f775ce; _gat=1; TG-TRACK-CODE=index_navigation; SEARCH_ID=88db5c7fa2464090a6dd7041f35074ba; X_HTTP_TOKEN=492369107a1a20441020ab9b771f2f6d; sensorsdata2015jssdkcross=%7B%22distinct_id%22%3A%221675489482d244-0f3ef5ad6aef94-4313362-2073600-1675489482e36f%22%2C%22%24device_id%22%3A%221675489482d244-0f3ef5ad6aef94-4313362-2073600-1675489482e36f%22%7D; sajssdk_2015_cross_new_user=1; ab_test_random_num=0; _putrc=69D503B669D896FC123F89F2B170EADC; login=true; hasDeliver=0; gate_login_token=33f3414d87f12e09e089b3b6daf10134f0a5ebf49fad63dfd9b8bc4e3a4f162b; unick=hello; LGRID=20181127174101-8d501f2b-f228-11e8-8c21-5254005c3644; Hm_lpvt_4233e74dff0ae5bd0a3d81c6ccf756e6=1543311662',
'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.102 Safari/537.36',
},
callback : function (error, res, done) {
if(error){
console.log(error);
done();
}else{
var $ = res.$;
var jobList = []
console.log($('title').text())
$('.con_list_item').each(function (idx, item) {
var $item = $(item);
jobList.push({
name: $item.find('.position_link').find('h3').text(),
address: $item.find('.add').find('em').text(),
company: $item.find('.company_name').find('a').text(),
companyLink: $item.find('a').attr('href'),
companyImg: $item.find('.com_logo').find('img').attr('src'),
money: $item.find('.money').text(),
label:$item.find('.list_item_bot').find('span').text(),
welfare:$item.find('.li_b_r').text()
});
});
try {
console.log('c.queueSize',c.queueSize);
console.log('jobList',jobList.length)
if(jobList.length > 0 ){
//保存到数据库中
dbo.collection("job").insertMany(jobList, function(err, res) {
if (err) throw err;
console.log('job 数据导入成功!');
// db.close();
})
}
done();
}catch(e){
console.log(e);
done();
}
}
}
});
//爬取首页的menu的数据
c.queue([
{
uri: 'https://www.lagou.com/',
headers:{
'Set-Cookie':'index_location_city='+encodeURI(location),
'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.102 Safari/537.36',
'JSESSIONID':'ABAAABAAAGFABEFC5E29AF672C4DAF0B10AEE494D83FD62',
'login':true
},
// The global callback won't be called
callback: function (error, res, done) {
if(error){
console.log(error);
}else{
var $ = res.$;
$('.menu_sub a').each(function (idx, element) {
var $element = $(element);
menuList.push({
name: $element.text(),
tjId: $element.attr('data-lg-tj-id'),
// tjIdName:changeName($element.attr('data-lg-tj-id')),
tjNo:$element.attr('data-lg-tj-no'),
tjCid:$element.attr('data-lg-tj-cid'),
link:$element.attr('href'),
});
//组装menu前30页的url
for(var i = 1 ;i<=30 ;i++){
urlList.push($element.attr('href')+i+'/');
}
});
//把首页爬取的menu URL数据加入到需要爬取的队列中
c.queue(urlList);
console.log(urlList,urlList.length)
console.log('menuList 共',menuList.length ,'条数据');
dbo.collection("menu").insertMany(menuList, function(err, res) {
if (err) throw err;
console.log('数据导入成功!');
// db.close();
})
}
done();
}
}])
res.render('craw');
});
});
module.exports = router;